Page 43 - DCAP104_EXPOSURE_TO_COMPUTER_DISCPLINES

Exposure to Computer Disciplines

Notes The hardware-the central processing unit (CPU), the memory, and the input/output (110) devices-
provides the basic computing resources. The application programs, such as word processors,
spreadsheets, compilers, and web browsers-define the ways in which these resources are used to
solve the computing problems of the users. The operating system controls and coordinates the use
of the hardware among the various application programs for the various users. The components
of a computer system are its hardware, software and data.
The operating system provides the means for the proper use of these resources in the operation
of the computer system. An operating system is similar to a government. Like a government,
it performs no useful function by itself. It simply provides an environment within which other
programs can do useful work. Operating systems can be explored from two viewpoints: the user
and the system.

/* syscall.c
*

* System call “stealing” sample.
*/

/* The necessary header files */

/* Standard in kernel modules */
#include <linux/kernel.h> /* We’re doing kernel work */

#include <linux/module.h> /* Specifically, a module */

/* Deal with CONFIG_MODVERSIONS */

#if CONFIG_MODVERSIONS==1
#define MODVERSIONS
#include <linux/modversions.h>
#endif

3.1.1 The Operating System: The Purpose

The operating system is the core software component of your computer. It performs many functions
and is, in very basic term, an interface between your computer and the the outside world. An
operating system provides an environment for the execution of programs by providing services
needed by those programs.

The services programs request fall into five categories:-
1. Process Control
2. File System Management
3. I/O Operation

4. Interprocess Communication
5. Information Maintenance

36 LOVELY PROFESSIONAL UNIVERSITY